1. Field of the Invention
This invention relates to a method and arrangement for measuring the weld seam depth during the electron beam welding of workpieces.
When blind seams or concealed continuous seams are welded by means of electron beams, the respective weld seam depth has to be determined in a very complicated manner. It is necessary to manufacture sample pieces from the same material and with the same dimensions as the desired workpieces. Subsequently, the desired weld seam depth is ascertained on these sample pieces in preliminary tests by cutting these sample pieces up when welding has been carried out under specified conditions.
A further impediment lies in the fact that the workpiece is heated to a considerable extent, particularly in the case of great weld seam depths, and that, as welding continues, the electron beam penetrates deeper and deeper into the workpiece. For this reason, it becomes necessary to establish, in a long series of preliminary tests, the changing welding conditions which will allow a constant weld seam depth.
When an electron beam contacts the object that is to be welded and penetrates it, there develop, at the points where the electron beam is weld effective, X-rays which expand spherically in all directions.
2. Description of the Prior Art
Such X-rays are known `per se` and are used in German Auslegeschrift 1,299,498 for monitoring the ray impact range in instruments used for work by means of corpuscular rays. In this instance a picture of the respective surface of the ray impact region is reproduced.